This invention is directed to an improved hinge mechanism, and more particularly, to a hinge having dual pivoting axes and a spring bias effective in only a portion of the hinge range of movement.
Hinges are used in various applications. One example of such use is the use of hinges for spa covers. When used in this capacity, the hinge is used to move the spa cover from its usage position atop the spa to a retracted position in which the spa tub is accessible to users. Many of these hinges comprise an arm connected between the spa cover and a pivot connected to a side of the spa housing. The pivot arm acts under continuous spring bias as the spa cover moves through its full range of motion from its usage position to its retracted position.
Experience has shown that spa cover hinges which now are commercially available have assorted deficiencies and problems, including complexity of parts and organization, lack of ruggedness, high levels of force required to operate them, especially if the cover must be moved against a spring bias throughout its movement from its usage position to its retracted position.
Accordingly, a need exists for an improved spa cover hinge system which seeks to avoid those and other deficiencies and problems found in currently available products.
The present invention provides an improved spa cover hinge system which seeks to avoid those and other deficiencies and problems found in currently available products. A presently preferred embodiment of the new spa cover hinge system is described below with reference to the accompanying drawings. The drawings depict the structures by which the lower end of each of a pair of swing arms is coupled to a spa housing for movement of the arm about multiple pivot axes relative to the spa housing. However, as noted below, a hinge embodying features and principles of this invention can be configured differently for use in other contexts and utilities.
Generally speaking, a hinge according to this invention comprises a base and a plate rotatably coupled to the base about a turn axis fixed in the base. The hinge further includes a swing member rotably coupled to the plate about a pivot axis fixed relative to the plate and a spring coupled between the base and the plate which urges the plate to rotate about the turn axis in a first direction. The plate has limited rotation in the first direction about the turn axis as the swing arm has limited movement relative to the plate about the pivot axis in a second direction, opposite of the first direction. The limited movement of the swing arm is defined by a pivot limit. Movement of the swing arm toward and away from the pivot limit occurs about the pivot axis without effect of the spring on the arm. During contact of the swing arm with the pivot limit, the arm and the plate can move about the turn axis against the effect of the spring.
In a presently preferred embodiment of the invention, the hinge is connectible between a spa housing and a spa cover which has a closed position atop the housing and an open position, where the spa cover is retracted away from atop the housing. The hinge includes a base plate which is attachable to a side of a spa housing, and a crank plate rotably coupled to the base plate about a first axis fixed in the base plate. A swing arm is rotably coupled at its proximal end to the crank plate about a second axis fixed in the crank plate and connectible to the spa cover at its distal end. A stop mounted onto the crank plate limits rotation of the swing arm about the second axis. A spring, operatively connected between the base plate and the crank plate, exerts a force on the crank plate creating a moment in a first rotational direction about the first axis. A spa cover connected to the arm at its distal end can travel along a path from its closed position to an open position. Along a first segment of the path, the crank plate does not rotate relative to the base plate, while along a second segment of the path, the crank plate turns about the second axis, acting against the force of the spring.